63 lines
2.4 KiB
JavaScript
63 lines
2.4 KiB
JavaScript
import { isPlainObject } from "../predicate/isPlainObject.mjs";
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import { isUnsafeProperty } from "../_internal/isUnsafeProperty.mjs";
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//#region src/object/merge.ts
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/**
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* Merges the properties of the source object into the target object.
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*
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* This function performs a deep merge, meaning nested objects and arrays are merged recursively.
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* If a property in the source object is an array or an object and the corresponding property in the target object is also an array or object, they will be merged.
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* If a property in the source object is undefined, it will not overwrite a defined property in the target object.
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*
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* Note that this function mutates the target object.
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*
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* @param {T} target - The target object into which the source object properties will be merged. This object is modified in place.
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* @param {S} source - The source object whose properties will be merged into the target object.
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* @returns {T & S} The updated target object with properties from the source object merged in.
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*
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* @template T - Type of the target object.
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* @template S - Type of the source object.
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*
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* @example
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* const target = { a: 1, b: { x: 1, y: 2 } };
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* const source = { b: { y: 3, z: 4 }, c: 5 };
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*
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* const result = merge(target, source);
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* console.log(result);
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* // Output: { a: 1, b: { x: 1, y: 3, z: 4 }, c: 5 }
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*
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* @example
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* const target = { a: [1, 2], b: { x: 1 } };
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* const source = { a: [3], b: { y: 2 } };
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*
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* const result = merge(target, source);
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* console.log(result);
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* // Output: { a: [3, 2], b: { x: 1, y: 2 } }
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*
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* @example
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* const target = { a: null };
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* const source = { a: [1, 2, 3] };
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*
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* const result = merge(target, source);
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* console.log(result);
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* // Output: { a: [1, 2, 3] }
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*/
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function merge(target, source) {
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const sourceKeys = Object.keys(source);
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for (let i = 0; i < sourceKeys.length; i++) {
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const key = sourceKeys[i];
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if (isUnsafeProperty(key)) continue;
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const sourceValue = source[key];
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const targetValue = target[key];
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if (isMergeableValue(sourceValue) && isMergeableValue(targetValue)) target[key] = merge(targetValue, sourceValue);
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else if (Array.isArray(sourceValue)) target[key] = merge([], sourceValue);
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else if (isPlainObject(sourceValue)) target[key] = merge({}, sourceValue);
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else if (targetValue === void 0 || sourceValue !== void 0) target[key] = sourceValue;
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}
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return target;
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}
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function isMergeableValue(value) {
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return isPlainObject(value) || Array.isArray(value);
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}
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//#endregion
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export { merge };
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